80 Free Online Calculators

Fast, free, no sign-up. Finance, pregnancy, health, math, statistics, geometry and unit conversions — every calculator runs entirely in your browser, so nothing you type is ever uploaded.

Finance Calculators

Loan payments, mortgage, interest, investment growth, retirement and tax calculators.

Amortization CalculatorCalculate the monthly payment, total interest, and full payoff schedule of an amortized loan such as a mortgage or car loan.
Annuity CalculatorFind the regular payment an annuity pays out, based on the lump sum invested, the interest rate, and how long it must last.
APR CalculatorSee the true annual percentage rate (APR) of a loan once upfront fees are included. APR is higher than the nominal rate whenever a lender charges fees.
Auto Lease CalculatorEstimate the monthly payment on a car lease from the capitalized cost, the residual value, the money factor, and your down payment.
Auto Loan CalculatorCalculate the monthly payment and total cost of a car loan, including how much your down payment saves you.
Bond CalculatorFind a bond's yield to maturity from its price, coupon rate, face value, and remaining years.
Compound Interest CalculatorSee how an initial balance plus regular contributions grows with compound interest.
Credit Card CalculatorFind out how many months it takes to pay off a credit card balance, and how much interest you pay along the way.
Future Value CalculatorFind what a sum of money today will be worth in the future at a given growth rate.
Inflation CalculatorSee how inflation raises the future price of goods and shrinks what your money will actually buy.
Simple Interest CalculatorCompute simple interest: interest earned on a principal at a fixed rate, with no compounding.
Investment CalculatorProject the growth of an investment that starts with a lump sum and grows with monthly contributions.
Loan CalculatorCompute the monthly payment and total interest for any fixed-rate loan.
Margin CalculatorCompute gross profit, gross margin percentage, and markup from revenue and cost of goods sold.
Mortgage CalculatorCalculate your full monthly mortgage payment including optional property tax and homeowner insurance.
Mortgage Payoff CalculatorSee how much time and interest you save by adding an extra amount to your monthly mortgage payment.
Pension CalculatorProject the size of your pension pot at retirement and the monthly income it could support.
Present Value CalculatorFind what a future sum of money is worth today, given a discount rate and time horizon.
Rent vs. Buy CalculatorCompare the economics of buying a home versus renting over the number of years you expect to stay.
Retirement CalculatorProject your retirement nest egg from current savings and contributions, and the income it can safely provide.
ROI CalculatorCalculate the return on investment: total percentage return, annualized return, and profit.
Salary CalculatorConvert an hourly wage into weekly, monthly, and yearly income, including overtime options.
Sales Tax CalculatorAdd sales tax to a pre-tax price, or work backwards from a tax-included total.
Tip CalculatorCalculate the tip, the total, and each person's share when splitting a bill.
Discount CalculatorSee the final price after a discount and exactly how much you save.
Fuel Cost CalculatorEstimate the fuel cost of a trip from the distance, your vehicle's consumption, and the fuel price.
Electricity Cost CalculatorFind what any appliance costs to run: watts, hours of use, and your electricity rate.

School Calculators

Grade averages, GPA, fractions, quadratic equations and combinations.

Grade CalculatorCompute your course grade: enter each score and its weight, and get the weighted average plus letter grade.
GPA CalculatorCalculate your GPA: enter the grade points for each course and its credit hours.
Fraction CalculatorAdd, subtract, multiply, or divide two fractions, with the result simplified and as a mixed number.
Quadratic Equation CalculatorSolve any quadratic equation ax² + bx + c = 0: discriminant, both roots (real or complex), and the vertex.
Combination CalculatorCalculate combinations nCr ("n choose r") and permutations nPr: how many ways to pick r items from n.

Date & Time Calculators

Age, days between dates, work hours and world time conversion.

Age CalculatorFind an exact age in years, months, and days from a date of birth, plus the countdown to the next birthday.
Date Difference CalculatorFind the exact number of days between two dates, plus weeks, months, and years equivalents.
Time Card CalculatorCalculate daily work hours from a start and end time, subtract the break, and optionally compute the pay.
World Time ConverterSet a time anywhere in the world and see the corresponding time in Paris, London, Tokyo, New York and 30 other destinations at once.

Pregnancy Calculators

Due date, ovulation, period tracking and pregnancy weight gain calculators.

Due Date CalculatorEstimate your due date from the first day of your last period and your usual cycle length.
Ovulation CalculatorFind your most fertile days and next estimated ovulation date based on your last period and cycle length.
Period CalculatorPredict when your next periods will arrive, based on your last period start and average cycle length.
Pregnancy CalculatorEnter your due date to see exactly where you are: current week and day, trimester, and countdown.
Pregnancy Weight Gain CalculatorSee the recommended weight gain for your pregnancy based on your pre-pregnancy BMI and current week.

Health Calculators

BMI, body fat and daily calorie calculators.

BMI CalculatorCalculate your Body Mass Index in metric or imperial units, with your weight category and healthy range.
Body Fat CalculatorEstimate your body fat percentage with the U.S. Navy tape method: only a tape measure needed.
Calorie CalculatorCalculate how many calories you burn per day (TDEE) and the targets for losing or gaining weight.
Ideal Weight CalculatorSee the classic ideal body weight for your height (Devine formula) plus the healthy BMI weight range.
Water Intake CalculatorEstimate how much water to drink per day based on your body weight and exercise.
Macro CalculatorSplit your daily calories into protein, carb, and fat grams for the diet style you choose.
Sleep CalculatorFind the best times to fall asleep so you wake up refreshed at your target wake-up time.

Home Calculators

Concrete and paint quantity calculators for home projects.

Concrete CalculatorCalculate how much concrete a slab needs: volume in cubic meters and yards, plus the number of bags.
Paint CalculatorEstimate how much paint a room needs: walls and ceiling, minus doors and windows, times the coats.

Math Calculators

Percentages, exponents, roots, factors, ratios and a scientific calculator.

Exponent CalculatorRaise a number to any power, including negative and fractional exponents.
Factor CalculatorFind the prime factorization and the complete list of factors of any integer.
Greatest Common Factor CalculatorFind the greatest common factor (GCF, also called GCD) of two to four integers.
Least Common Multiple CalculatorFind the least common multiple (LCM) of two to four integers.
Log CalculatorCompute a logarithm in any base, with the natural log and base-10 log shown alongside.
Percentage CalculatorThe four everyday percentage operations in one place: X% of Y, "X is what % of Y", percent change, and add/subtract a percent.
Ratio CalculatorSolve a proportion (A:B = C:?) and simplify any ratio to its lowest terms.
Root CalculatorCompute any root: square root, cube root, or any n-th root of a number.
Rounding CalculatorRound a number to any number of decimals: nearest, always up, or always down.
Scientific CalculatorEvaluate expressions with full operator precedence: parentheses, powers, multiplication before addition, and percent.

Statistics Calculators

Standard deviation, z-score, probability, sample size and number sequences.

Number Sequence CalculatorExplore arithmetic and geometric sequences: nth term, the first terms, and the sum of the first n.
Probability CalculatorCompute the union, intersection, and conditional probabilities of two events A and B.
Sample Size CalculatorHow many responses does a survey need? Compute the sample size from margin of error and confidence level.
Standard Deviation CalculatorPaste a list of numbers to get the mean, median, variance, and both sample and population standard deviation.
Z-score CalculatorConvert a raw score into a z-score and percentile, or a z-score back into a raw score.

Geometry Calculators

Area, volume, triangles, circles, the Pythagorean theorem and distance.

Area CalculatorCalculate the area of common two-dimensional shapes.
Circle CalculatorGet the area, circumference, and diameter of a circle from its radius.
Distance CalculatorFind the distance between two points, in 2D or 3D, from their coordinates.
Pythagorean Theorem CalculatorApply a² + b² = c²: find the hypotenuse or a missing leg of a right triangle.
Right Triangle CalculatorSolve a complete right triangle: enter two legs, a leg plus the hypotenuse, or the hypotenuse plus an angle.
Slope CalculatorFind the slope, the y-intercept, and the full line equation through two points.
Surface Area CalculatorCalculate the surface area of common 3D solids.
Triangle CalculatorEnter the three sides of any triangle to get its area, perimeter, angles, and type.
Volume CalculatorCalculate the volume of common 3D solids.

Conversion Calculators

Miles/km, liters/gallons, feet/meters, ounces/grams and temperature conversions.

Miles to KM CalculatorConvert miles to kilometers and back. One mile is exactly 1.609344 kilometers.
KM to Miles CalculatorConvert kilometers to miles and back. One kilometer is 0.621371 miles.
Liters to Gallons CalculatorConvert liters to U.S. gallons and back.
Feet to Meters CalculatorConvert feet to meters and back, including feet-and-inches to meters.
Ounces to Grams CalculatorConvert ounces to grams and back: cooking, nutrition labels, and gold weights.
Celsius to Fahrenheit CalculatorConvert between Celsius and Fahrenheit temperatures in either direction.

Why CalcMate?

Every calculator is a clean, single-purpose page: enter your numbers, get your answer instantly, and see the formula behind it. We believe a good calculator should explain itself — each page shows exactly how the result is computed, so you can trust it and learn from it.

All calculations happen locally in your browser with plain JavaScript. No accounts, no tracking walls, no "download our app".